int main()
{  	 	       	  
    int num,time,save;//分别为选择的方案编号，实际通话时间，存款
    int temp_money,temp_time,temp_save;//对应方案的月租，通话额度，预存款
    double ans;
    scanf("%d,%d,%d",&num,&time,&save);                        //1
    switch(num){//按照方案预设相应的月租与通话额度
        case 1:
            temp_money = 28;
            temp_time = 200;
            break;
         case 2:
            temp_money = 48;
            temp_time = 500;
            break;
         case 3:
            temp_money = 68;
            temp_time = 800;
            break;
         default:                                           //1
            printf("Error");                                //1
            return 0;
    }
    switch(save){                                            //1
        case 200:                                            //1
            temp_save = 300;
            break;                                           //1
        case 300:
            temp_save = 500;
            break;
        case 500:
            temp_save = 800;
            break;
        default:
            printf("Error");//没有该存款的优惠方案
            return 0;
    }
if(time <= temp_time)                                       //1
    ans = temp_save - temp_money;                           //1
else
    ans = temp_save - temp_money -(time - temp_time)*0.25;  //1
printf("remainder=%.2f",ans);                                         //1
return 0;
}